Artur Beterbiev didn’t feel right for three days after taking a massive shot during his professional debut.

The Russian freight train is one of the most intimidating fighters to ever step foot between the ropes and carries serious power in both hands.

VideotronBeterbiev knocked out Christian Cruz in the second round in his pro debut[/caption]

Beterbiev has knocked out all 20 of his professional opponents and is currently in possession of three of the four major sanctioning body belts at light heavyweight (WBC, IBF and WBO).

On Saturday night, he gets the opportunity to collect the final piece of the undisputed puzzle when he squares off against WBA champion Dmitry Bivol in a long-awaited all-Russian clash.

Before blazing his path of destruction through the paid ranks, Beterbiev met Christian Cruz in his maiden appearance as a pro back in 2013.

It was a fairly routine stoppage victory for Beterbiev, who blasted Cruz out inside two rounds without much hassle.

On paper, it doesn’t appear to be a particularly noteworthy fight but the 39-year-old remembers it well – particularly, one concussive blow.

“Everyone hits very well because it is boxing and we are in small gloves – even in my first fight when I turned professional. ,” Beterbiev told talkSPORT.com.

“I never had a WSB (World Series of Boxing) fight which is not really professional but half and half.

“I remember in my first professional fight, he hit me on my head and it was very painful.

“I remember that… His name was Christian Cruz.

“In the amateurs, it never happened because the gloves are different, even when you get punched here it doesn’t feel like this.

Beterbiev is the only world champion with a 100 per cent KO ratioGETTY

“But when he punched me, for three days it was not working,” he laughed as he pointed to his head.

Beterbiev was an excellent amateur, winning two European Championships and a World Championship during his 300-plus fight tenure.

The only major amateur medal he wasn’t able to pick up was an Olympic one.

At the 2008 Beijing Games he fell to a highly controversial round of 16 defeat against local boxer Zhang Xiaoping, who went on to scoop the gold medal that year.

Meanwhile, at London 2012 he edged out Michael Hunter before being knocked out of the tournament by eventual winner Oleksandr Usyk in the quarter-finals.

This marked the third and final time Beterbiev and Usyk locked horns.

Beterbiev scored a points victory over the Ukrainian in their inaugural encounter back in 2007 and dropped him in their rematch with a body shot four years later at the World Championships – although Usyk got his hand raised in the end.